2012年大学英语六级语法：时态

会计考友

时态  
  M- `# P8 i8 e/ v4 h　　1)现在完成进行时态 (have/has been + -ing 分词构成): 动作或状态从过去某时开始,继续到现在,可能继续下去,也可能刚刚结束.
: l* b" I- r8 l# ^' M3 @$ j# r　　I’ve been writing letters for an hour.
　　I’ve been sitting in the garden.
　　2)过去完成进行时(由had been + ing分词构成): 过去某个时刻以前一直在进行的动作
. J( p. F) k9 }! X% b' F, M　　I’d been working for some time when he called.
　　We had been waiting for her for two hours by the time she came. www.Examw.com
$ W$ O1 A' W9 x" x　　3)将来完成进行时: 将来某个时刻以前一直在进行的动作.
2 v8 @. E' C! V& S5 J. `% E　　By next summer, he will have been working here for twenty years.
　　In another month’s time she’ll have been studying here for three years.
　　4)将来完成时(由shall/will have + 过去分词构成): 将来某时会业已发生的事.
　　I shall have finished this one before lunch.
　　They’ll have hit the year’s target by the end of October.